While Americans are working three times faster than ever, they’re also popping speed at their jobs in epidemic proportions.

A report yesterday says workers are devouring amphetamines – both legal and illegal versions – in record amounts at their jobs, with use up a staggering 44 percent in the past year.

Other drug abuse at work – namely use of cocaine, marijuana, opiates and hallucinogens – is down or flat, according to the report by laboratory giant Quest Diagnostics.

But hyperactivity-inducing speed is becoming the drug de jour in the workplace because it makes people believe they’re more alert, peppier and more decisive, the report noted.

“Employees on amphetamines may be doing their work faster, but they’re probably doing it wrong – faster,” said Dr. Barry Sample, director of science and technology at Quest’s employee testing programs.

Tests were conducted on more than 7 million workers at companies ranging from Wall Street and entertainment businesses to retailing and the services industries.

Sample said illegal speed appears to be driving the binge of amphetamines and methamphetamines, which include prescription diet pills.

Workplace use of suspected bootleg speed is up 68 percent this year.

The report didn’t break down drug use by gender or age, but Sample said it covers the spectrum of payrolls, from executives to clerks.

The U.S. Bureau of Labor Statistics says the rate of increase in worker productivity is a near-record of 5.2 percent this year, nearly triple the average 2 percent rate during 1994 to 2001.

Speed also causes whacked-out workers.

“Besides the health dangers, amphetamines bring a higher absenteeism and tardiness at work- as well as increased irritability, talkativeness, aggressiveness, argumentativness and nervousness,” Sample said.